Change the namespace declaration in the application descriptor.
For example, to update version 1.0 to 1.5, change:
<application xmlns="http://ns.adobe.com/air/application/1.0." ...
Thanx for replying my dear friend.but i think you got the wrong one or i may be unable to make u understand...
My question is that, suppose if we have an Adobe Air 1.5 installed on our system and adobe released adobe 1.6.......then what code or where we have to make the change so that our adobe air 1.5 updated itself from 1.5 to 1.6.
You can download the installer for the new version from Adobe's web site. The runtime will update itself automatically (it checks on a regular schedule). Also if you install an AIR application that requires a later version, the runtime will update itself before installing that application.